Joining Dissimilar Metals Need Impact Testing? (Section VIII Div. 1)

[CoFe2]

Hello All,

I am trying to figure out when to implement or invoke a WPS with impact testing for welding 2205 duplex material.

I am looking at UHA-51 (e) "Exemptions from Impact Testing for Welding Procedure Qualifications. For Welding Procedure Qualifications,impact testing is not required for the following combinations of weld metals and MDMTs except as modified in (c):"

(3) for the following weld metal, when the base metal of similar chemistry is exempt as stated in (d)(3), then the weld metal shall also be exempt at MDMTs of -20°F (-29°C) and warmer: (-a) austenitic ferritic duplex steels (-b) ferritic chromium stainless steels; (-c) martensitic chromium stainless steels. Carbon content as used in (2) above is for weld metal produced with the addition of filler metal.

With some context here is the scenario: So if I am welding 2205 duplex, lets say a fillet weld in joining a 1-1/2" thick plate to a 3/8" thick plate, knowing my 1-1/2" thick plate is not exempt from base metal impact testing my mind tells me because per para (e) (3) I would invoke a weld procedure that has impact testing with it, I side conservative knowing that the 3/8" plate is exempt but the 1-1/2" plate is not (right or wrong I am not positive). So now I move on to what if I am welding a piece of carbon steel or austenitic stainless steel that is exempt from impact testing to that same piece of 1-1/2" 2205 duplex that is not exempt do I need a WPS welding those dissimilar metals that I performed impact testing on?

Thanks in advance. Let me know what you think, anything is helpful.

 

[gtaw]

Somewhere in the recesses of my mind it seems that I remember the thickness used to decide if impact testing is required is the weld size when the base metals are not the same thickness.

Best regards - Al

 

[SnTMan]

CoFe2, it is a curious (to me) Code fact that all the explanatory material presented in Part UCS is missing in Part UHA. Especially relevant to your questions is the definition of "governing thickness". Pretty straightforward in Part UCS, totally missing in Part UHA. One could perhaps reason from the definitions in UW-40(f) although strictly speaking this part only applies to Post Weld Heat Treat.

Under this interpretation, your first example would be governed by the fillet weld throat dimension (UW-40(f)(3)). If thicker than 3/8:, impact test. I am assuming 2205 weld metal here.

The second example is muddier still. But I'd say each base metal and the weld metal must be exempted on its own. I feel that for this example that the procedure must be impact tested even if the filler is exempt due to the non-exempted 2205 base metal.

Grey area for sure.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

CoFe2
Is this a real example or is it for fun?
Do you have a drawing?
How do you extract the CHARPY test specimen in a fillet weld for Welding Procedure Qualification?
Did you read ASME IX?
I don't think it will pass the bend test for fillet weld, even less the CHARPY test

Regards

 

[CoFe2]

Sorry for the late response everyone.

Thanks SnTMan I think that option 1 as you laid out was how it has been treated for many years within our organization, and talking to others around the industry.

r6155, This is a real example, unfortunately I am not at the liberty to share much in regards of drawings. The scenario is this, we have a 1-1/4" thick tubesheet with base metal impact testing required that gets welded to the shell, this tube sheet internally is separating the 3/8" thick 2205 "channel" from the 1/2" carbon steel shell, both material exempt from impact testing. The joint consists of internal fillet welds for each side and for lack of a better explanation a multi-pass grove weld with backing (tubesheet) for the exterior if that makes sense (maybe I could draw up an example).

The procedures I have and plan on doing will be qualified by grove welds to establish variables. Have not found too much in section IX yet but could probably look harder, seemed more like a section VIII div. 1 question as far as when to invoke the procedure rather than how to.

Thanks for the help!

 

Code logic would suggest that the base metal with the less stringent requirement rules.
I'll bet there is an interpretation asking this same question.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[r6155]

CoFe2
You need to consult a welding engineer.

Regards

 

[SnTMan]

IM, did you mean more stringent? Kind of been my experience...

The problem with sloppy work is that the supply FAR EXCEEDS the demand